In the movies there are lots of things that have been alterd or missed while watching the movie...

"Episode 1, 2 and 4 Obi-Wan's Drinking problem?"

"In all the movies where Obi-Wan is playing (a live), he takes a drink and soon after he uses his light saber (mostly to cut of arms)
In Episode I he takes a drink on the Trade Federations space ship and soon after fights the Battle droids
In Episode II he takes a drink at the Coruscant Nightclub and then slices of the arm of the bounty hunter Zam Wessel
In Episode IV he takes a drink at the Mos Eisley Cantina and cuts of the arm of Dr. Evazan.
This could also explains why he uses his mind trick on Stormtroopers by saying "You don't need to see my identification."

"Episode 2, Jango's head
When Jango Fett battles Mace Windu, his blaster is cut of and soon after his head. If you look in slow motion you see the head falling to the ground. First you see a shadow if you go a bit forward you see two shadows (on of the helmet and one of the head). The helmet falls to the ground and you can look in side and see that it is empty."

'Episode 1, Protocol Droids
When Jar Jar is playing with the pit droid in Watto's Junkshop, in the background there is a protocol droid looking like C-3PO. Anakin was taking parts from it to build C-3PO. But the metal coverings look like the once that are on C-3PO in Episode II. Also the left leg is missing. In Episode IV-VI C-3PO has a silver leg instead of a golden one.
Episode 1, Daughter of George Lucas
In the scene where Anakin in finishing his Pos Racer, his friends are coming to see if Anakin wants to play.
The girl in the red, the tallest girl with braces is the daughter of George Lucas, Katie Lucas."

Episode 5, Potato in space
During The Empire Strikes Back's famous asteroid scene, one of the deadly, hurling asteroids is actually... a potato !

Episode 4, Stormtrooper is to long
In Star Wars, in the scene where C-3PO and R2-D2 are hiding into a closet in a control room and that the stormtroopers force the entry door, one of them knocks his head as he enters.

Episode 2, Everyone in to the Bar
In Attack of the Clone there is a scene where Anakin and Obi-Wan enter the Outlander Club. If you pay good attention you see two familiar figures. One (on the left) is Anthony Daniels who has played C-3PO in all the movies. The other one is Ahmed Best (on the right) who played Jar Jar Binks. They both play conman who do business in the club. Anthony Daniels plays Lieutenant Dannl Faytonni and Ahmed Best Achk Med-Beq

Episode 2, More Lucas children
Katie Lucas already had a role in Episode I but she is also in Attack of the Clones as Nightclub Dancer. Try if you can spot her in the Outlander Club. She Twi'lek with a black dress and brown sqarfs hanging from her arms. She can be seen when Anakin and Obi-Wan enter the bar and Obi-Wan walks to the bar to get a drink. Anakin passes her in the next scene (on the left). When Obi-Wan cuts of the arm of Zam Wesell, she can be seen again talking to Achk Med-Beq (Jar Jar) also on the left of the screen.
Lucas son Jett is also in the movie dressed as one of the Jedi children under training.

Episode 1, Jedi Master, Knight
The opening scroll of Episode I, states:
"The Supreme Chancellor has secretly dispatched two Jedi Knights, the Guardians of peace and justice in the galaxy"

But who are the two Jedi Knights. They meen Obi-Wan and Qui-Gon Jinn, but Obi-Wan is a Padawan and Qui-Gon is Jedi Master. It would have been correct if it just stated "two Jedi"